How heavy was Einstein’s brain? Does the size of your brain say anything about intelligence?

Longer answer

It’s well-established that intelligence originates in the brain. This has led many to assume that a larger brain equals higher intelligence. However, researchers from McMaster University discovered that Einstein’s brain weighed only 1,230 grams – significantly less than the average male brain, which weighs around 1,400 grams (Witelson, Kigar, & Harvey, 1999). Instead, they attributed Einstein’s remarkable intellect to his parietal lobes, crucial for mathematical, visual, and spatial reasoning. Interestingly, Einstein’s parietal lobes were 15% wider than an average person’s. So, was Einstein’s lighter brain an anomaly, or does brain size have little bearing on intelligence?

IQ and Brain Size

In 2015, a comprehensive meta-analysis sought to answer this question (Pietschnig, Penke, Wicherts, Zeiler, & Voracek, 2015). This study combined data from 88 research papers involving over 8,000 participants to examine the relationship between brain size and intelligence. The findings showed a weak correlation: individuals with larger brains tended to have slightly higher IQs. However, the relationship identified in the analysis was very weak; brain volume accounted for only about 6% of the variation in IQ. This means that while it’s possible to estimate someone’s IQ based on their brain size, such estimates are likely to be inaccurate in many cases, as most variations in intelligence result from other factors. According to Jakob Pietschnig, one of the researchers involved in the meta-analysis, brain structure appears more significant for IQ than brain size (‘Larger brains do not lead to high IQs, new meta-analysis finds,’ 2015).

Conclusion

In Einstein’s case, the width of his parietal lobes may have played a significant role in his extraordinary intellect. Nevertheless, scientific research highlights the involvement of many other brain regions and factors in determining intelligence. To complicate matters further, the extent to which each factor contributes to IQ varies between individuals. Much remains to be uncovered about the brain before we can draw meaningful conclusions about intelligence based solely on its physical attributes.

Read more:

• Larger brains do not lead to high IQs, new meta-analysis finds. (2015)
• Pietschnig, J., Penke, L., Wicherts, J. M., Zeiler, M., & Voracek, M. (2015). Meta-analysis of associations between human brain volume and intelligence differences: How strong are they and what do they mean? Neuroscience & Biobehavioral Reviews, 57, 411-432.
• Witelson, S. F., Kigar, D. L., & Harvey, T. (1999). The exceptional brain of Albert Einstein. Lancet, 353(9170), 2149-2153.